. The computing environment in most medium-sized and large enterprises involves old main-frame based (legacy) applications and systems as well as new workstation-based distributed computing systems. The objective of the METEOR project is to support multi-system workflow applications that automate enterprise operations. This paper deals with the modeling and specification of workflows in such applications. Tasks in our heterogeneous environment can be submitted through different types of interfaces on different processing entities. We first present a computational model for workflows that captures the behavior of both transactional and nontransactional tasks of different types. We then develop two languages for specifying a workflow at different levels of abstraction: the Workflow Specification Language (WFSL) is a declarative rulebased language used to express the application-level interactions between multiple tasks, while the Task Specification Language (TSL) focuses on the issues re...

Workflow management is primarily concerned with dependencies between the tasks of a workflow, to ensure correct control flow and data flow. Transaction management, on the other hand, is concerned with preserving data dependencies by preventing execution of conflicting operations from multiple, concurrently executing tasks or transactions. In this paper we argue that many applications will be served better if the properties of transaction and workflow models are supported by an integrated architecture. We also present preliminary ideas towards such an architecture.

The Internet and the proliferation of inexpensive computing power in the form of clusters of workstations or PCs provide the basic hardware infrastructure for business to business electronic commerce in small and medium enterprises. Unfortunately, the corresponding software infrastructure is still missing. In this paper we show a way to develop appropriate tools for electronic commerce by describing the approach we have taken in the WISE project (Workflow based Interned SErvices). The goals of WISE are to develop and deploy the software infrastructure necessary to support business to business electronic commerce in the form of virtual enterprises. The idea is to combine the tools and services of different companies as building blocks of a higher level system in which a process acts as the blueprint for control and data flow within the virtual enterprise. From this idea, the final goal is to build the basic support for an Internet trading community where enterprises can join their serv...

Unlike distributed transactions, mobile transactions do not originate and end at the same site. The implication of the movement of such transactions is that classical atomicity, concurrency and recovery solutions must be revisited to capture the movement behavior. As an effort in this direction, we define a model of mobile transactions by building on the concepts of split transactions and global transactions in a multidatabase environment. Our view of mobile transactions, called Kangaroo Transactions, incorporates the property that transactions in a mobile computing system hop from one base station to another as the mobile unit moves through cells. Our model is the first to capture this movement behavior as well as the data behavior which reflects the access to data located in databases throughout the static network. The mobile behavior is dynamic and is realized in our model via the use of split operations. The data access behavior is captured by using the idea of global and local transactions in a multidatabase system. This research was partially supported by the National Science Foundation under Grant Number INT-9417907 and by a Massive Digital Data System (MDDS) effort sponsored by the Advanced Research and Development Committee of the Community Management Staff. Part of this research was performed while Margaret Dunham (then Margaret Eich) was on sabbatical at the University of Queensland in Brisbane, Australia. y This research was partially supported by Hughes Research Laboratories under Grant Number 906356. 1 1

Current workflow management systems still lack support for dynamic and automatic workflow adaptations. However, this functionality is a major requirement for next-generation workflow systems to provide sufficient flexibility to cope with unexpected failure events. We present the concepts and implementation of AGENTWORK, an event-based workflow management system supporting automated workflow adaptations in a comprehensive way. In particular, AGENTWORK uses temporal estimates to determine which remaining parts of running workflows are affected by an exception and is able to predictively perform suitable workflow adaptations. This helps ensure that necessary adaptations are performed in time with minimal user interaction which is especially valuable in complex applications such as for medical treatments.

Workflow systems seek to provide an implementation vehicle for complex, recurring business processes. Notwithstanding this common objective, there are a variety of distinct features offered by commercial workflow management systems. These differences result in significant variations in the ability of distinct tools to represent and implement the plethora of requirements that may arise in contemporary business processes. Many of these requirements recur quite frequently during the requirements analysis activity for workflow systems and abstractions of these requirements serve as a useful means of identifying the key components of workflow languages. Previous work has identified a number of workflow control patterns which characterise the range of control flow constructs that might be encountered when modelling and analysing workflow. In this paper, we describe a series of workflow data patterns that aim to capture the various ways in which data is represented and utilised in workflows. By delineating these patterns in a form that is independent of specific workflow technologies and modelling languages, we are able to provide a comprehensive treatment of the workflow data perspective and we subsequently use these patterns as the basis for a detailed comparison of a number of commercially available workflow management systems and business process modelling languages.

A workflow is an activity involving the coordinated execution of multiple tasks performed by different processing entities [KS95]. These tasks could be manual, or automated, either created specifically for the purpose of the workflow application being developed, or possibly already existing as legacy

Workflow management systems (WFMSs) coordinate the execution of applications distributed over networks. In WFMSs, data inconsistencies can arise due to (i) the interaction between steps of concurrent threads within a workflow (intra-workflow coordination) (ii) the interaction between steps of concurrent workflows (interworkflow coordination) and (iii) the presence of failures. Since these problems have not received adequate attention, this paper focuses on developing the necessary concepts and infrastructure to handle them. First, to deal with inter- and intra- workflow coordination requirements we have identified a set of high level building blocks. Secondly, to handle failures we propose a novel and pragmatic approach called opportunistic compensation and re-execution that allows a workflow designer to customize workflow recovery from correctness as well as performance perspectives. Thirdly, based on these concepts we have designed a workflow specification language that expresses ne...

Practical workflow systems need to be able to tolerate deviations from the initial process model because of un-anticipated situations. They should also be able to accommodate deviations in the format of the forms and data being manipulated. We offer a framework for treating both kinds of deviations uniformly, by applying ideas from programming languages (with workflow agents as potential on-line exception handlers) to workows that have been reified as objects in classes with special attributes. As a result, only a small number of new constructs, which can be applied orthogonally, need to be introduced. Special run-time checks are used to deal with the consequences of permitting deviations from the norm to persist as violations of constraints.

There is an increasing interest in changing information systems to support business processes in a more direct way. This means to actively deliver tasks to be performed to the right persons at the right point in time with the necessary information and application functions needed for performing this task. Process-oriented workflow technology is a very interesting candidate to achieve this goal. In fact, many companies have already started to implement information systems based on this kind of technology. Hence the important question arises, how far do we get using this technology. Is the functionality provided powerful enough to support a wide range of application scenarios or is it only suitable for rather simple applications? And, if the latter is the case, are the missing functions of the "just to do" type or are more fundamental issues addressed? The paper uses the clinical application scenario to explain, to motivate, and to elaborate the functionality needed to adequately support...